Is there a hidden trick to Improved Mog Throw?

It seems after I collect a certain number of hidden items with Improved Mog Throw in any given area, Mog starts finding nothing but 1 gil. Is there something to this? And if so, is there a way to 'reset' it so items start appearing again? I wonder because I'm still a long way off from having the materials required to purchase two of each Delicate Genji item (I'm trying to collect doubles of every accessory).